Broadhead arrowheads are well known in the bow hunting art. In particular, broadheads having auxiliary blades that deploy when the arrow strikes its target are also well known, and will be referred to generally as expanding or expandable broadheads.
Expandable broadheads allow an arrowhead to have a relatively small and streamlined configuration during flight to enhance accuracy. Upon striking a target, a set of auxiliary blades expand for the purpose of enlarging the entrance wound, enabling a more certain and humane kill.
U.S. Pat. No. 6,517,454 (Barrie et al) discloses a broadhead with sliding, expanding blades. The blades are pivotally attached to the arrowhead and are held closed in flight by a rubber restraint. When the arrowhead penetrates the target, the forward edges of the blades also contact the target forcing the blades rearward, severing the restraint and allowing the trailing edges of the blades to dispose outward to a V-shape thereby exposing the sharpened edges of the blades.
Published U.S. Patent Application 2009/0029811 (Bolen III) discloses an expandable broadhead and blades therefor. In Bolen, the auxiliary blades face forward with the pivots for them positioned at the rear of the arrowhead. The blades are configured to fracture if, when they expand and strike the target, they encounter a hard or solid object, such as a bone.
U.S. Pat. No. 6,554,727 (Armstrong et al) discloses a deflection-resistant arrowhead having both fixed and mechanically expandable blades. In Armstrong, the blades have a rearward pivot and face forward, and are held in place by a severable restraint during flight. When the arrowhead strikes the target, a forward edge of each expandable blade also contacts the target forcing the blades rearward around the pivot to open and thus expose the sharpened edges of the blades.
U.S. Pat. No. 6,595,881 (Grace Jr.) discloses an expanding blade-archery broadhead with the blades, in their stored position, facing forward and having a rear or trailing pivot. A sliding collar deploys forward when the arrowhead strikes its target causing the blades to extend and pivot rearward, exposing the sharpened blade edges.
U.S. Pat. No. 6,669,586 (Barrie et al) discloses an expanding broadhead having expandable blades with forward pivots attached to a collar that is slidably mounted within the arrowhead body. When the arrowhead strikes the target, the mounting ring is brought into contact with a camming surface within the arrowhead which deploys the sharpened edges of the blades by severing the restraint.
U.S. Pat. No. 6,910,979 (Barrie et al) discloses an expandable broadhead with expandable blades having arcuate slots formed thereon. The blades are mounted to the arrowhead with a guide boss positioned within the slot. When the arrowhead penetrates the target, the lead edge of each blade comes into contact with the target of the blade is forced along the arcuate slot to deploy with the sharpened blade edges exposed.
U.S. Pat. No. 7,226,375 (Sanford) discloses an expandable arrow broadhead for attachment to one end of an arrow shaft. A set of rearward extending blades, pivoted at their front end are attached to an arrowhead and are held in place by a rubber band. When the arrow strikes its target, a collar within the arrowhead slides forward contacting the blades forcing them outward with sufficient force to sever the rubber band and deploy the sharpened cutting edges.
The foregoing references are incorporated herein in their entirety.